Blackjack

Provably fair

Verify fairness

The session's seed decides every card. Its hash was committed before the first hand; the seed is revealed when the session ends. Each round's cards come from HMAC-SHA256 keyed by the seed over the round's number and the bettor's own seed.

Seed hash

1c0125938ff482b8b3e07357a1c3502d53c676524e84161a915790027f73ea7c

Seed

b29bf65fa6d8cd72c1281910c2f49935d0464d08f5789f18b6a5e57581707d75 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

0a7bf534b34461c94bd86e32d5e3887f

Commitment

Batch 48,906, Merkle root a03963fefccf9af2400f64f55caf97e72fef0b7459ebdf659da546ebd70c0f1b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 25d3c8900e7a6a04157afe3fbeac240bf91da9da94601486ca1d4b7b176f49b3

Checked: the seed hash proves into the root.

To check it yourself, take the session's proof:

1. Hash the seed as above and compare it with the seed hash; prove the seed hash into the root with the Merkle path (keccak256, as for every match).
2. For each round: round seed = HMAC-SHA256(key = seed, "degen.house.round.v1" ‖ 0x00 ‖ u64be(length of the bettor's seed) ‖ bettor's seed ‖ u64be(round)).
3. Key ChaCha20 (RFC 8439, zero nonce) with the round seed and read little-endian 64-bit words; a card is the next word below 2⁶⁴ − 1 − ((2⁶⁴ − 1) mod 52), modulo 52.
4. Replay the round's actions with the game's rules: the cards and the payout must match.

The replay plays every hand rebuilt this way on the server from the same data, and marks any that does not rebuild as recorded.